Superplasticity in a two-phase Mg-8Li-2Zn alloy processed by two-pass extrusion

作者：Liu, Xuhe; Zhan, Haibo; Gu, Shihai; Qu, Zhikun; Wu, Ruizhi^*; Zhang, Milin

来源：Materials Science and Engineering A-Structural Materials Properties Microstructure and Processing, 2011, 528(19-20): 6157-6162.

DOI：10.1016/j.msea.2011.04.073

• Mg-Li alloy
• Superplastic
• Deformation mechanism

Tensile tests on a two-pass extruded Mg-8Li-2Zn alloy are conducted at 473-593 K, and an initial strain rate of 1.5 x 10(-4)-7.5 x 10(-3) s(-1). The two-pass extruded alloy has refined structure and excellent superplastic properties, with a maximum recorded elongation of 758% at 563 K under an initial strain rate of 1.5 x 10(-4) s(-1). The value of the strain rate sensitivity under the optimum superplastic condition is 0.55, and the activation energy is 90 kJ/mol. These indicate that the dominant deformation mechanism in the two-pass extruded alloy is grain-boundary sliding controlled by grain-boundary diffusion. Coalescence and interlinkage of cavities are the reasons for tensile failure.

• 出版日期2011-7-25
• 单位哈尔滨工程大学